Ready-to-assemble furniture continues to grow in popularity. The number of retail outlets selling ready-to-assemble furniture continues to grow both domestically and internationally with a number of retailers having an international presence. The manufacturing and production of ready-to-assemble furniture is also global. Retailers, both domestic and international, may purchase ready-to-assemble furniture from factories in a number of countries throughout the world, shipping into central distribution centers to be redistributed out to their retail outlets. Many of these distribution centers are highly automated with sophisticated conveyor systems to sort and move products extremely efficiently and economically. Because these companies exist in a highly competitive environment, reducing costs and increasing efficiency are paramount to being and remaining competitive and profitable. Therefore, improving logistics is a continuous process. Reducing the cubic measure of cartoning and packaging by using construction methods which utilize factory manufactured sub-assemblies which nest allows more items to be loaded within semi-trailers and shipping containers reducing the freight cost per item for both brick-and-mortar and ecommerce retailers; saves on warehouse space, conveyorizes more efficiently and requires less shelf space in a retail outlet.
Freight costs, which are independent of manufacturing costs, offer their own potential area of cost reduction. The more units which can be loaded into trailers, containers and other shipping vessels, the more the per unit cost can be reduced. Therefore, the actual landed cost—unit cost plus freight cost plus duties, insurance and other related costs—is reduced. The positive affect of this is that the savings can be passed along to customers or used to improve gross margins and profits. When parts can be designed and manufactured to be nested within one another, the cubic volume of the packaged unit can be reduced leading to tangible and beneficial savings for organizations.
With consumers having more demanding schedules, saving time becomes important. A key resistance to ready-to assemble furniture is the time spent assembling and the difficulty in assembling units as well as the confusion often caused by poorly written instructions. Reducing and simplifying the assembly experience is critical to the success of each item as well as the growth of the ready-to-assemble industry. As an example, a growing category within the ready-to-assemble industry is “no tools required” product. As the name implies, consumers can take product out of its packaging and assemble without the need of tools. Although this puts sever limits on how sophisticated products can be designed, in the consumers' eyes it is time saving and simple to assemble. For many items such as basic bookcases, tables, plant stands and the like function and low cost is more important than design. For more fashionably designed product it is, therefore, desirable to be able to manufacture ready-to-assemble furniture which incorporates current trends and styles but is also cost efficient in both manufacturing and logistics and quick and simple to assemble. Minimizing the number of parts needing to be assembled and the number of tools needed to do the assembly contribute to making ready-to-assembly products consumer friendly. Fewer parts also means fewer joints (which can loosen over time) leading to sturdier, more stable units once assembled.
In reviewing the prior art, U.S. Pat. No. 4,563,040 to Alster, the assembly of shown table or chair is accomplished with individual parts assembled into the desired configuration. Because of the large number of parts individually connected to one another, a large number of joints are created, generating more points of weakness within the structure. The stress generated at each joint results in a loosening effect, transferred from joint to joint as the unit racks from use. In using wood dowels and wood nuts referred to as “rod caps,” only a limited amount of torque is able to be applied to secure each connection. With such a large number of individual parts, units constructed using the Alster system also take a significant amount of time to assemble which consumers see as a negative feature. It also is a time consuming chore to retighten all of these joints. Additionally, U.S. Pat. No. 719,837 to Morton; U.S. Pat. No. 1,813,072 to Murdock; U.S. Pat. No. 4,261,667 to Ervin et al., the use of individual and separate parts and not sub-assemblies and the inability to apply sufficient torque, and in some cases, no torque at all, will, over time, generate weaker joints. A common weakness in all of these systems, therefore, is the number of joints created using such a large number of individual parts. Without being able to generate enough torque during assembly the joints cannot be made sufficiently rigid to withstand normal wear and tear without racking. Nor is there a way to quickly retighten each individual part at each joint when joints do loosen—a natural occurrence when the units are used as envisaged. The “MODULAR KNOCKDOWN CHAIR”, U.S. Pat. No. 5,407,250 to Prince et al. also has the same weaknesses as found in the prior art surveyed above, but does suggest a pre-assembled back and seat, but not incorporating the back legs or front legs into a sub-assembly. It also discloses the limited use of mortise and tenon joints in FIG. 4 using a wood screw to secure the joint. The joint based on a wood screw made of metal into a wood part, particularly in a rocking chair as shown in FIG. 3 of Prince et al., will quickly lose much of its holding power and, in all likelihood, strip out if tightened too aggressively. In U.S. Pat. No. 233,478 to Creager, a back leg and front leg assembly is envisioned, but weaknesses are again created with the number of joints and lack, in this case, of any torque being applied to create a strong rigid connection resistant to racking. The joint envisaged in Creager appears to be a glued joint with no mechanical fastening devises.
All of these noted systems have inherent weaknesses which the embodiment of this invention overcomes. Listed below are additional relevant patents:    U.S. Pat. No. 693,197 February 1902 White    U.S. Pat. No. 1,432,349 October 1922 McFarland    U.S. Pat. No. 3,374,353 July 1973 Lupinsky    U.S. Pat. No. 4,008,971 February 1977 Wah et al.    U.S. Pat. No. 4,030,846 June 1977 Flototto    U.S. Pat. No. 4,261,665 April 1981 Hsiung    U.S. Pat. No. 4,280,269 July 1981 Marini    U.S. Pat. No. 4,691,965 September 1987 Hsiung    U.S. Pat. No. 4,958,425 September 1990 Gomes    U.S. Pat. No. 5,088,180 February 1992 Nottingham et al.    U.S. Pat. No. 5,277,476 January 1994 Caldwell    U.S. Pat. No. 5,720,457 February 1998 Miller et al.    U.S. Pat. No. 5,601,340 February 1997 Stout    U.S. Pat. No. 5,810,505 September 1998 Henriott et al.    U.S. Pat. No. 7,404,607 B2 July 2008 Crue